Adhesive film and optical display device containing the same

Abstract

To provide an adhesive film with excellent rollability and impact resistance. [Solution] The present invention provides an adhesive film comprising a first region and a second region having different storage moduli, wherein the first region and the second region satisfy formulas 1 and 2, and an optical display device including the same. [Formula 1] 0.01 ≤ G'(25℃ / B) / G'(25℃ / A) ≤ 0.2 (In the above formula 1, G'(25°C / A) is the storage modulus at 25°C in the first region, and G'(25°C / B) is the storage modulus at 25°C in the second region.) [Formula 2] 0.1 ≤ G'(60℃ / B) / G'(60℃ / A) ≤ 0.5 (In the above formula 2, G'(60°C / A) is the storage modulus at 60°C in the first region, and G'(60°C / B) is the storage modulus at 60°C in the second region).

Description

Technical Field

[0001] The present invention relates to an adhesive film and an optical display device including the same.

Background Art

[0002] An optical display device includes a display element including a window film, a conductive film, an organic light-emitting element, etc. A touch pad has a structure in which a transparent adhesive layer (OCA, optical clear adhesive) is laminated between a window film and a conductive film. The transparent adhesive layer may be laminated between two of a window film, a conductive film, a polarizing plate, and an organic light-emitting element. In recent years, a flexible display device has been developed as an optical display device.

[0003] In a flexible display device, various optical elements included in the device need to have flexibility. Since the transparent adhesive layer is formed between a window film and a conductive film, the adhesive force on both sides must be excellent. In addition, the transparent adhesive layer must have good flexibility and holding properties. In particular, a flexible display device can include a bending region where bending occurs and a non-bending region where bending is not required. Generally, the bending region can be a part where a user folds the flexible display device. The non-bending region is located around the bending region and can be a part where a user grasps the flexible display device, etc. In the bending region, the flexibility and holding properties must be good. And in the non-bending region, it is necessary to prevent dents of the transparent adhesive layer, breakage and / or deformation of the organic light-emitting element panel.

[0004] The background art of the present invention is disclosed in Patent Document 1.

Prior Art Document

Patent Document

[0005]

Patent Document 1

[0006] This invention provides an adhesive film with excellent rollability and impact resistance. [Means for solving the problem]

[0007] According to one embodiment, an adhesive film can be provided.

[0008] The adhesive film comprises a first region and a second region, each having a different storage modulus, and the first and second regions satisfy the following equations 1 and 2: [Formula 1] 0.01≦G'(25℃ / B) / G'(25℃ / A)≦0.2 (In formula 1, G'(25℃ / A) is the storage modulus at 25℃ in the first region. G'(25℃ / B) is the storage modulus at 25℃ in the second region. [Formula 2] 0.1≦G'(60℃ / B) / G'(60℃ / A)≦0.5 (In formula 2, G'(60℃ / A) is the storage modulus at 60℃ in the first region. G'(60℃ / B) is the storage modulus at 60℃ in the second region.

[0009] According to one embodiment, an optical display device can be provided.

[0010] The optical display device includes an adhesive film. [Effects of the Invention]

[0011] This allows us to provide an adhesive film that offers both excellent rollability and impact resistance. [Brief explanation of the drawing]

[0012] [Figure 1]Figure 1 is a cross-sectional view of an adhesive film according to one embodiment. [Figure 2] Figure 2 is a schematic diagram of the adhesive film before and after rolling in one embodiment. [Figure 3] Figure 3 is a schematic diagram of the method for evaluating rollable reliability. [Modes for carrying out the invention]

[0013] The embodiments of the present invention will be described in detail with reference to the accompanying drawings so that they can be easily implemented by a person skilled in the art to which the present invention pertains. The present invention can be implemented in a variety of different forms and is not limited to the embodiments and examples described herein. In the drawings, parts that are not relevant to the description have been omitted in order to clearly illustrate the present invention, and the same or similar components are denoted by the same reference numerals throughout the specification.

[0014] In this specification, "upper" and "lower" are defined based on the drawings, and depending on the viewing point, "upper" may become "lower" and "lower" may become "upper." What is referred to as "on" may include not only directly above but also cases where another structure is interposed in between. On the other hand, what is referred to as "directly on" or "immediately above" means that there is no other structure interposed in between.

[0015] In this specification, "(meth)acrylic" may mean acrylic and / or methacrylic.

[0016] In this specification, "polymer" may include oligomers, polymers, or resins.

[0017] The present invention provides an adhesive film having excellent rollable physical properties and impact resistance. The adhesive film includes a first region and a second region described below. In one embodiment, the adhesive film consists of a first region and a second region, and the first region and the second region are integrally formed as a single layer, and have excellent rollable physical properties and impact resistance. Therefore, the adhesive film can be used for a rollable display device.

[0018] Hereinafter, an adhesive film according to an embodiment of the present invention will be described.

[0019] The adhesive film includes regions having different storage elastic moduli in one plane. Specifically, the adhesive film includes a first region and a second region. In one embodiment, the adhesive film consists of a first region and a second region, and the storage elastic moduli of the first region and the second region are different from each other at the same measurement temperature.

[0020] FIG. 1 is a conceptual diagram of an adhesive film according to an embodiment. Referring to FIG. 1, the adhesive film consists of a first region 100 and a second region 200, and the first region 100 and the second region 200 are integrally formed with each other.

[0021] Referring to FIG. 1, the adhesive film consists of only two regions in the order of the first region 100 and the second region 200 based on the lateral direction of the outermost surface of the adhesive film, and either one of the outermost surfaces in the longitudinal direction of the adhesive film forms the first region 100, and the other one of the outermost surfaces in the longitudinal direction of the adhesive film forms the second region 200.

[0022] The first region and the second region satisfy the following Mathematical Formulas 1 and 2: [Mathematical Formula 1] 0.01 ≦ G’(25°C / B) / G’(25°C / A) ≦ 0.2 (In Mathematical Formula 1, G’(25°C / A) is the storage elastic modulus of the first region at 25°C G’(25°C / B) is the storage elastic modulus of the second region at 25°C) [Mathematical Formula 2] 0.1≦G'(60℃ / B) / G'(60℃ / A)≦0.5 (In formula 2, G'(60℃ / A) is the storage modulus at 60℃ in the first region. G'(60℃ / B) is the storage modulus at 60℃ in the second region.

[0023] Formulas 1 and 2 serve as criteria for determining whether impact resistance in the first region and rollability in the second region can be achieved simultaneously. The first region may be a non-rollable region when applied to a display device. The second region may be a rollable region. The first region must have excellent impact resistance in exchange for the lack of rollability. On the other hand, the second region must have excellent rollability. If the second region is formed on only one side of the first region and the second region becomes rollable, the first region will be affected by the second region. The first and second regions have the relationship shown in Formulas 1 and 2, which allows for a good balance between impact resistance from the first region and rollability from the second region.

[0024] In one embodiment, G'(25℃ / B) / G'(25℃ / A) may be 0.05 to 0.2 or 0.1 to 0.2.

[0025] In one embodiment, G'(60℃ / B) / G'(60℃ / A) may be 0.1~0.4, 0.1~0.3, or 0.1~0.2.

[0026] The adhesive film may have a thickness of 5 μm to 50 μm, for example, 5 μm to 30 μm.

[0027] According to one embodiment, the first region and the second region may be a pressure-sensitive adhesive film (PSA).

[0028] The following provides a detailed explanation of the first and second domains.

[0029] 1st area The first region may be located in a non-rollable portion when the adhesive film is applied to an optical display device. Because the first region has excellent impact resistance, applying the adhesive film to an optical display device can protect the optical elements.

[0030] In the first region, the storage modulus at 25°C may be between 0.01 MPa and 10 MPa, for example, between 0.05 MPa and 1 MPa, or between 0.1 MPa and 0.8 MPa. Within this range, the range of Equation 1 can be easily reached.

[0031] In the first region, the storage modulus at 60°C may be between 0.005 MPa and 1 MPa, for example, between 0.01 MPa and 0.2 MPa, or between 0.05 MPa and 0.1 MPa. Within this range, the range of Equation 2 can be easily reached.

[0032] In the first region, the creep measured at 60°C may be 10% or more, for example, 10% to 50% or 10% to 40%. Within this range, excellent peel strength and reliability can be achieved.

[0033] The first region may include a photocured product of a composition for the first region comprising a monomer mixture and an initiator. The composition for the first region may further include a crosslinking agent. The composition for the first region may further include additives.

[0034] The composition for the first region may include monomer mixtures and initiators for (meth)acrylic copolymers having hydroxyl groups. The monomer mixture may be included in the composition for the first region in the form of monomer mixtures that have not undergone any polymerization, or it may be included in the composition for the first region as a partially polymerized monomer mixture in which part of the monomer mixture has been partially polymerized.

[0035] The monomer mixture can form a hydroxyl-containing (meth)acrylic copolymer. This hydroxyl-containing (meth)acrylic copolymer can form a matrix in the first region and exhibit tackiness. The hydroxyl-containing (meth)acrylic copolymer may have a glass transition temperature of -100°C to 10°C, specifically -70°C to 0°C. Within this range, the adhesive film exhibits excellent tackiness and reliability over a wide temperature range. The hydroxyl-containing (meth)acrylic copolymer may have a refractive index of 1.35 to 1.70, specifically 1.40 to 1.60. Within this range, transparency can be maintained when laminated with another optical film.

[0036] The monomer mixture may include alkyl group-containing (meth)acrylates and alicyclic group-containing (meth)acrylates. The monomer mixture may further include hydroxyl group-containing (meth)acrylates and heteroalicyclic group-containing vinyl monomers or (meth)acrylic monomers.

[0037] In one embodiment, the total amount of alkyl group-containing (meth)acrylate, alicyclic group-containing (meth)acrylate, hydroxyl group-containing (meth)acrylate, and heteroalicyclic group-containing vinyl monomer or (meth)acrylic monomer may be present in the monomer mixture in an amount of 95% by weight or more, for example, 95% to 100% by weight, or 100% by weight.

[0038] Alkyl-containing (meth)acrylates may include monofunctional (meth)acrylic acid esters having an unsubstituted linear or branched alkyl group having 1 to 20 carbon atoms.

[0039] Alkyl-containing (meth)acrylates may include, for example, one or more of 2-ethylhexyl (meth)acrylate, n-butyl (meth)acrylate, isooctyl (meth)acrylate, propyl (meth)acrylate, t-butyl (meth)acrylate, iso-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, and decyl (meth)acrylate, preferably one or more of 2-ethylhexyl (meth)acrylate, n-butyl (meth)acrylate, and isooctyl (meth)acrylate, more preferably 2-ethylhexyl (meth)acrylate.

[0040] Alkyl-containing (meth)acrylates may be included in the monomer mixture in amounts of 10% to 80% by weight, for example, 30% to 80% by weight or 30% to 50% by weight. Within this range, the adhesive strength and durability reliability of the adhesive film can be further improved.

[0041] Alicyclic group-containing (meth)acrylates may include (meth)acrylic acid esters having substituted or unsubstituted alicyclic groups with 5 to 15 carbon atoms in the ester moiety. Isobornyl (meth)acrylate can be used as the alicyclic group-containing (meth)acrylate.

[0042] Alicyclic group-containing (meth)acrylates may be included in the monomer mixture in an amount of 10% to 60% by weight, for example, 30% to 40% by weight. Within this range, the adhesive strength and durability reliability of the adhesive film can be further improved.

[0043] Hydroxyl group-containing (meth)acrylates can provide adhesive strength to adhesive films. The glass transition temperature of the homopolymer of the hydroxyl group-containing (meth)acrylate may be 0°C to -40°C, preferably -10°C to -40°C, and more preferably -20°C to -40°C. Within this range, the adhesive strength and flexural reliability of the adhesive film can be enhanced.

[0044] The hydroxyl group-containing (meth)acrylate may be a monofunctional (meth)acrylic acid ester having a linear or branched alkyl group with 1 to 20 carbon atoms and containing one or more hydroxyl groups. For example, the hydroxyl group-containing (meth)acrylate may be one or more of 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, or 6-hydroxyhexyl (meth)acrylate.

[0045] Hydroxyl group-containing (meth)acrylate may be present in the monomer mixture in amounts of 0% to 40% by weight, for example, 5% to 40% by weight, 10% to 40% by weight, 10% to 30% by weight, or 10% to 20% by weight. Within this range, the adhesive strength and durability reliability of the adhesive film can be further improved.

[0046] The heteroalicyclic group-containing vinyl monomer or (meth)acrylic monomer may be a vinyl or (meth)acrylic monomer having a heteroalicyclic group having 3 to 10 carbon atoms, with one or more elements of oxygen, sulfur, and nitrogen constituting the ring. The heteroalicyclic group-containing vinyl or (meth)acrylic monomer may also be one or more of (meth)acryloylmorpholine or vinylpyrrolidone.

[0047] Heteroalicyclic group-containing vinyl monomers or (meth)acrylic monomers may be included in the monomer mixture in amounts of 0% to 30% by weight, for example, 1% to 30% by weight, 5% to 30% by weight, or 5% to 10% by weight. Within this range, the adhesive strength and durability reliability of the adhesive film can be further improved.

[0048] The monomer mixture may further contain copolymerizable monomers in addition to the monomers listed above. The copolymerizable monomers may include one or more amine group-containing monomers, alkylene glycol group-containing monomers, silane group-containing monomers, and aromatic group-containing monomers.

[0049] Initiators can be used to cure (partially polymerize) monomer mixtures with (meth)acrylic copolymers or to cure viscous liquids with films. Initiators may contain one or more photopolymerization initiators and thermal polymerization initiators.

[0050] Any photopolymerization initiator that can induce the polymerization reaction of the following radical polymerizable compounds during the curing process by light irradiation or the like can be used. For example, benzoin-based, hydroxyketone-based, aminoketone-based, or phosphine oxide-based photoinitiators can be used, specifically benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin isobutyl ether, 2,2-dimethoxy-2-phenylacetophenone, 2,2'-diethoxyacetophenone, 2,2'-dibutoxyacetophenone, 2-hydroxy-2-methylpropiophenone, pt-butyltrichloroacetophenone, pt-butyldichloroacetophenone, 4-chloroacetophenone, 2,2'-dichloro-4-phenoxyacetophenone, and other acetophenone compounds, dimethylaninoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropane-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butane-1- 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)ketone, benzophenone, p-phenylbenzophenone, 4,4-non-cydiethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone, 2-aminoanthraquinone, 2-methylanthraquinone Examples include thioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethyl ketal, acetophenone dimethyl ketal, p-dimethylaminobenzoic acid ester, oligo[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone], and 2,4,6-trimethylbenzoyl-diphenylphosphine oxide. In this application, one or more of these may be used, but are not limited thereto.

[0051] The thermal polymerization initiator is not particularly limited as long as it has the aforementioned physical properties, and conventional initiators such as azo compounds, peroxide compounds, or redox compounds can be used.Examples of azo compounds include 2,2-azobis(2-methylbutyronitrile), 2,2-triazobis(isobutyronitrile), 2,2-triazobis(2,4-dimethylvaleronitrile), 2,2-nitrazobis-2-hydroxymethylpropionitrile, dimethyl-2,2-methylazobis(2-methylpropinate), and 2,2-pioazobis(4-methoxy-2,4-dimethylvaleronitrile), and others. Examples of peroxide compounds include inorganic peroxides such as potassium perlactate, ammonium persulfate, or hydrogen peroxide; or diacin. Peroxide, peroxydicarbonate, peroxyester, tetramethylbutyl peroxyneodecanoate, bis(4-butylcyclohexyl) peroxydicarbonate, di(2-ethylhexyl) peroxycarbonate, butyl peroxyneodecanoate, dipropyl peroxydicarbonate, diisopropyl peroxydicarbonate, diethoxyethyl peroxydicarbonate, diethoxyhexyl peroxydicarbonate, hexyl peroxydicarbonate, dimethoxybutyl peroxydicarbonate, bis(3-methylbutyl) Toxy-3-methoxybutyl) peroxydicarbonate, dibutyl peroxydicarbonate, dicetyl peroxydicarbonate, dimyristyl peroxydicarbonate, 1,1,3,3-tetramethylbutyl peroxypivalate, hexyl peroxypivalate, butyl peroxypivalate, trimethylhexanoyl peroxide, dimethylhydroxybutyl peroxyneodecanoate, amyl peroxyneodecanoate, butyl peroxyneodecanoate Examples of organic peroxides include t-butyl peroxyneoheptanoate, amyl peroxypivalate, t-butyl peroxypivalate, t-amyl peroxy-2-ethylhexanoate, lauryl peroxide, dilauroyl peroxide, didecanoyl peroxide, benzoyl peroxide, or dibenzoyl peroxide. Examples of redox compounds include, but are not limited to, mixtures of peroxide compounds and reducing agents.In this application, one or more azo, peroxide, or redox compounds can be used.

[0052] The initiator may be present in an amount of 0.0001 to 5 parts by weight, specifically 0.001 to 3 parts by weight, or more specifically 0.001 to 1 part by weight, per 100 parts by weight of the monomer mixture. Within this range, the curing reaction can be carried out completely, preventing residual initiator that reduces permeability, minimizing bubble formation, and achieving excellent reactivity.

[0053] The composition for the first domain may further contain one or more of the crosslinking agent and additives.

[0054] The crosslinking agent may include one or more (meth)acrylates with two or more functionalities, for example, one or more with two to six functionalities. Examples of crosslinking agents include 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, neopentyl glycol adipate di(meth)acrylate, dicyclopentanyl di(meth)acrylate, caprolactone-modified dicyclopentenyl di(meth)acrylate, ethylene oxide-modified di(meth)acrylate, and di(meth)acryloxyester. Isocyanurate, allylated cyclohexyl di(meth)acrylate, tricyclodecane dimethanol(meth)acrylate, dimethylol dicyclopentane di(meth)acrylate, ethylene oxide modified hexahydrophthalate di(meth)acrylate, tricyclodecane dimethanol(meth)acrylate, neopentyl glycol modified trimethylpropane di(meth)acrylate, adamantane di(meth)acrylate, or 9,9-bis[4-(2-acrylate] Examples of difunctional (meth)acrylates include, but are not limited to, difunctional (meth)acrylates such as [royloxyethoxy)phenyl]fluorene; trifunctional (meth)acrylates such as trimethylolpropane tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, propionic acid-modified dipentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propylene oxide-modified trimethylolpropane tri(meth)acrylate, or tris(meth)acryloxyethyl isocyanurate; tetrafunctional (meth)acrylates such as diglycerin tetra(meth)acrylate or pentaerythritol tetra(meth)acrylate; pentafunctional (meth)acrylates such as dipentaerythritol penta(meth)acrylate; and hexafunctional acrylates such as dipentaerythritol hexa(meth)acrylate and caprolactone-modified dipentaerythritol hexa(meth)acrylate.

[0055] The crosslinking agent may be included in an amount of 0.0001 to 5 parts by weight, specifically 0.1 to 5 parts by weight, or more specifically 0.5 to 1 part by weight, per 100 parts by weight of the monomer mixture.

[0056] The additive may include a silane coupling agent.

[0057] Silane coupling agents can further enhance the peeling force of adhesive films. Silane coupling agents may include conventional silane coupling agents known to those skilled in the art. For example, silane coupling agents may include, but are not limited to, epoxy group-containing silane coupling agents such as glycidoxypropyltrimethoxysilane and glycidoxypropylmethyldimethoxysilane.

[0058] The silane coupling agent may be included in an amount of 0.0001 to 5 parts by weight, specifically 0.1 to 5 parts by weight, or more specifically 0.5 to 1 part by weight, per 100 parts by weight of the monomer mixture.

[0059] The composition may further contain additives other than silane coupling agents. These additives may include, but are not limited to, one or more of the following: UV absorbers, reaction inhibitors, adhesion enhancers, thixotropy-inducing agents, conductivity-inducing agents, dye modifiers, stabilizers, antioxidants, leveling agents, and antistatic agents. The composition, i.e., the content of additives in the first region, can be appropriately selected within a range that does not affect the effects of the present invention.

[0060] 2nd area The second region may be located on the rollable portion when the adhesive film is applied to the optical display device. The second region can provide a holding effect when the adhesive film is applied to the optical display device.

[0061] In the second region, the storage modulus at 25°C may be between 0.001 MPa and 1 MPa, for example, between 0.005 MPa and 0.1 MPa, or between 0.01 MPa and 0.1 MPa. Within this range, the range of Equation 1 can be easily reached.

[0062] In the second region, the storage modulus at 60°C may be between 0.0005 MPa and 0.1 MPa, for example, between 0.005 MPa and 0.05 MPa, or between 0.01 MPa and 0.1 MPa. Within this range, the range of Equation 2 can be easily reached.

[0063] In the second region, the creep measured at 60°C may be 10% or more, for example, 10% to 50%. Within this range, excellent peel strength and rolling reliability can be achieved.

[0064] The second region may include a photocured product of a composition for the second region comprising a monomer mixture and an initiator. The composition for the second region may further include a crosslinking agent. The composition for the second region may further include additives.

[0065] The monomer mixture may be included in the composition for the second region in the form of a monomer mixture in which no polymerization has occurred at all, or it may be included as a partially polymerized monomer mixture in which some polymerization has occurred.

[0066] The monomer mixture can form a hydroxyl-containing (meth)acrylic copolymer. The hydroxyl-containing acrylic (meth)polymer can form a matrix in the second region and exhibit tackiness. The hydroxyl-containing (meth)acrylic copolymer may have a glass transition temperature of -100°C to 10°C, specifically -70°C to 0°C. Within this range, the adhesive film exhibits excellent tackiness and reliability over a wide temperature range. The hydroxyl-containing (meth)acrylic copolymer may have a refractive index of 1.35 to 1.70, specifically 1.40 to 1.60. Within this range, transparency can be maintained when laminated with another optical film.

[0067] The monomer mixture may include alkyl group-containing (meth)acrylates, hydroxyl group-containing (meth)acrylates, and alkylene glycol group-containing (meth)acrylates.

[0068] In one embodiment, the total amount of alkyl group-containing (meth)acrylate, hydroxyl group-containing (meth)acrylate, and alkylene glycol group-containing (meth)acrylate may be 95% by weight or more, for example, 95% to 100% by weight, or 100% by weight, in the monomer mixture.

[0069] The specific types of alkyl group-containing (meth)acrylates are substantially the same as those described in the Compositions of Area 1.

[0070] Alkyl-containing (meth)acrylates may be included in the monomer mixture in amounts of 10% to 80% by weight, for example, 40% to 80% by weight or 50% to 60% by weight. Within this range, the adhesive strength and durability reliability of the adhesive film can be further improved.

[0071] The specific types of hydroxyl group-containing (meth)acrylates are substantially the same as those described in the composition section of Area 1.

[0072] Hydroxyl group-containing (meth)acrylate may be included in the monomer mixture in amounts of 10% to 40% by weight, for example, 10% to 30% by weight or 10% to 20% by weight. Within this range, the adhesive strength and durability reliability of the adhesive film can be further improved.

[0073] Alkylene glycol group-containing (meth)acrylates may include (meth)acrylic acid esters having an alkylene glycol group, such as an ethylene glycol group or a propylene glycol group, in the ester moiety. For example, alkylene glycol group-containing (meth)acrylates may include one or more of 2-ethylhexyltriethylene glycol (meth)acrylate, methoxytriethylene glycol (meth)acrylate, phenoxytriethylene glycol (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, and phenoxypolyethylene glycol (meth)acrylate.

[0074] Alkylene glycol group-containing (meth)acrylate may be included in the monomer mixture in amounts of 10% to 50% by weight, for example, 10% to 40% by weight or 20% to 30% by weight. Within this range, the adhesive strength and durability reliability of the adhesive film can be further improved.

[0075] The monomer mixture may further contain copolymerizable monomers in addition to the monomers listed above. The copolymerizable monomers may include one or more amine group-containing monomers, alkylene glycol group-containing monomers, silane group-containing monomers, and aromatic group-containing monomers.

[0076] The specific type of initiator may be substantially the same as the initiator described in the composition of the first region.

[0077] The initiator may be included in an amount of 0.0001 to 5 parts by weight, specifically 0.001 to 3 parts by weight, or more specifically 0.001 to 1 part by weight, per 100 parts by weight of the monomer mixture. Within this range, the curing reaction can be carried out completely, preventing residual initiator that reduces permeability, minimizing bubble formation, and achieving excellent reactivity.

[0078] The composition for the second domain may further contain one or more crosslinking agents and additives.

[0079] The crosslinking agents and additives may be substantially the same as those described in the composition for the first region.

[0080] The crosslinking agent may be included in an amount of 0.0001 to 5 parts by weight, specifically 0.1 to 5 parts by weight, or more specifically 0.5 to 1 part by weight, per 100 parts by weight of the monomer mixture.

[0081] The silane coupling agent may be included in an amount of 0.0001 to 5 parts by weight, specifically 0.1 to 5 parts by weight, or more specifically 0.5 to 1 part by weight, per 100 parts by weight of the monomer mixture.

[0082] Manufacturing of adhesive films The adhesive film is manufactured by applying a first-area composition and a second-area composition to a release film at predetermined thicknesses, thereby producing a first-area coating and a second-area coating, while the first-area coating and the second-area coating are manufactured in contact with each other. Subsequently, the entire first-area coating and the second-area coating can be photocured to the same intensity.

[0083] The optical display device of the present invention includes the adhesive film of the present invention. The optical display device may include an organic light-emitting element display device, a liquid crystal display device, etc. The optical display device may include a flexible display device. However, the optical display device may also include a non-flexible display device. [Examples]

[0084] The structure and operation of the present invention will be described in more detail below through preferred embodiments of the present invention. However, these are presented as preferred examples of the present invention and should not be construed as limiting the present invention in any way.

[0085] Example 1 Manufacturing of compositions for the first domain To 100 parts by weight of a monomer mixture containing 40% by weight of 2-EHA (2-ethylhexyl acrylate), 40% by weight of IBOA (isobornyl acrylate), 10% by weight of 4-HBA (4-hydroxybutyl acrylate), and 10% by weight of ACMO (acryloylmorpholine), 0.005 parts by weight of Irgacure651 (2,2-dimethoxy-2-phenylacetophenone, BASF) was thoroughly mixed in a reactor as a photopolymerization initiator. After replacing the dissolved oxygen in the reactor with nitrogen gas, the mixture was partially polymerized by irradiation with ultraviolet light using a low-pressure mercury lamp (BL Lamp manufactured by Sankyo) to obtain a solution containing an acrylic copolymer with a viscosity of approximately 1000 CPS.

[0086] To a solution containing an acrylic copolymer, 0.3 parts by weight of Irgacure651 (2,2-dimethoxy-2-phenylacetophenone, BASF) as a photoinitiator, 1 part by weight of 1,6-hexanediol diacrylate as a crosslinking agent, and 0.2 parts by weight of 3-glycidoxypropyltriethoxysilane as a silane coupling agent were added per 100 parts by weight of the monomer mixture and mixed to produce a composition for the first region.

[0087] Manufacturing of compositions for the second region To 100 parts by weight of a monomer mixture containing 60% by weight of 2-EHA (2-ethylhexyl acrylate), 20% by weight of 4-HBA (4-hydroxybutyl acrylate), and 20% by weight of EHDG-AT (methoxytriethylene glycol acrylate), 0.005 parts by weight of Irgacure651 (2,2-dimethoxy-2-phenylacetophenone, BASF) was thoroughly mixed in a reactor. The dissolved oxygen in the reactor was then replaced with nitrogen gas in the same manner, and the mixture was partially polymerized by irradiating it with ultraviolet light using a low-pressure mercury lamp (BL Lamp manufactured by Sankyo) to obtain a solution containing an acrylic copolymer with a viscosity of approximately 1000 CPS.

[0088] To a solution containing an acrylic copolymer, 0.3 parts by weight of Irgacure651 (2,2-dimethoxy-2-phenylacetophenone, BASF) as a photoinitiator, 0.1 parts by weight of 1,6-hexanediol diacrylate as a crosslinking agent, and 0.2 parts by weight of 3-glycidoxypropyltriethoxysilane as a silane coupling agent were added to 100 parts by weight of the monomer mixture and mixed to produce a composition for the second region.

[0089] A first region composition, manufactured for use in a polyethylene terephthalate (PET) film, which is a release film, was applied to a predetermined thickness to form a first region coating. A second region composition, manufactured in contact with the formed first region coating, was then applied to the same thickness to form a second region coating. The first region coating and the second region coating were in contact with each other.

[0090] A PET film is further applied to the entire coating film for the first and second regions, and then exposed to ultraviolet light at 2000 mJ / cm². 2 By irradiating with light of a certain intensity, an adhesive sheet consisting of a PET film, an adhesive film (thickness: 25 μm) composed of a first region and a second region, and a PET film was manufactured.

[0091] Examples 2 to 4 An adhesive film was manufactured in the same manner as in Example 1, except that the components of the composition forming the first and second regions were changed as shown in Table 1 below.

[0092] Comparative Examples 1 to 5

[0093] An adhesive film was manufactured in the same manner as in Example 1, except that the components of the composition forming the first and second regions were changed as shown in Table 1 below.

[0094] The physical properties of the adhesive layers produced in the examples and comparative examples were evaluated as shown in Table 1 below, and the results are recorded in Table 1 below.

[0095] (1) Storage modulus (unit: MPa): The viscoelasticity of the first and second regions in the adhesive film was measured using an ARES (MCR-501 from Anton Paar), a dynamic viscoelasticity measuring device, under auto-strain conditions with a shear rate of 1 rad / sec and a strain of 1%. After removing all of the PET release film from the adhesive sheet, the first and second regions were laminated to a thickness of 500 μm each, and the laminates were perforated with an 8 mm diameter perforator to be used as specimens. The storage modulus was measured at a temperature rise rate of 5 °C / min from -60 °C to 90 °C, and the storage modulus was determined at 25 °C and 60 °C.

[0096] (2) Impact resistance: After peeling off the release PET film from the adhesive sheets manufactured in the examples and comparative examples, a polyurethane film (thickness: 100 μm, room temperature Young's modulus of elasticity 100 MPa CPU) was attached to the peeled surface. After peeling off the remaining release PET film from the adhesive sheet, a PET film (thickness: 50 μm, TU-94, SKC) was attached, and the sheets were laminated onto a glass substrate using an acrylic adhesive sheet.

[0097] A pen with a diameter of 0.7 mm and a circular cross-section was dropped vertically onto the first region of a specimen laminated in the following order: polyurethane film / adhesive film / PET film / acrylic adhesive sheet / glass. The polyurethane film and adhesive film were removed, and the presence of a dent in the PET film was checked using a 3D microscope (VK-X1100, Keyence Corporation). The height at which the dent or impact occurred was measured, and the corresponding height was evaluated as follows: ◎ if 13 cm or more, ○ if 10 cm or more but less than 13 cm, △ if 7 cm or more but less than 10 cm, and × if less than 7 cm.

[0098] (3) Rollable reliability: After peeling off the release PET film from the adhesive sheets manufactured in the examples and comparative examples, a polyurethane film (thickness: 100 μm, room temperature Young's modulus of elasticity 100 MPa CPU) was attached to the peeled surface. After peeling off the remaining release PET film from the adhesive sheet, a PET film (thickness: 50 μm, TU-94, SKC) was attached to prepare a test specimen. At this time, the polyurethane film was positioned on the outermost edge of the test specimen. After positioning a circular rod with a diameter of 3 mm as the axis in the center of the second region of the adhesive film, the ends of the first and second regions were grasped and the rod was manually rolled to repeatedly wrap and unwrap the test specimen. Figure 3 illustrates the method for evaluating rollable reliability, and includes a portion 10 containing the first region and a portion 20 containing the second region of the adhesive film. After placing a circular rod 30 between the portion 10 containing the first region and the portion 20 containing the second region of the adhesive film, the portion 10 containing the first region and the portion 20 containing the second region were pulled in the same direction.

[0099] If no cracks and / or delamination occurred at the boundary between the second and first regions of the adhesive film, it was evaluated as ○; if cracks and / or delamination occurred, it was evaluated as ×.

[0100] (4) Creep (unit: %): Multiple first regions of the adhesive film were stacked to produce a test specimen with a thickness of 800 μm. The strain values ​​of the produced test specimen were measured at 60°C with a force of 1N and at 600 sec using a DHR rheometer (TA Instruments).

[0101] [Table 1]

[0102] As shown in Table 1, the adhesive film according to this embodiment exhibited excellent rollability and impact resistance.

[0103] However, the comparative adhesive films that did not satisfy Equations 1 and 2 failed to achieve the effects described in this study.

[0104] Simple modifications or alterations of the present invention can be readily carried out by a person with ordinary skill in the art, and all such modifications or alterations can be considered to fall within the scope of the present invention. [Explanation of Symbols]

[0105] 10 Part containing the first region, 20 Part containing the second region, 30 Circular rod, 100 First region, 200 Second region

Claims

1. An adhesive film comprising a first region and a second region having different storage moduli, wherein the first region and the second region satisfy the following equations 1 and 2: [Formula 1] 0.01≦G'(25℃ / B) / G'(25℃ / A)≦0.2 (In the above formula 1, G'(25°C / A) is the storage modulus at 25°C in the first region. G'(25°C / B) is the storage modulus at 25°C in the second region. [Formula 2] 0.1≦G'(60℃ / B) / G'(60℃ / A)≦0.5 (In the above formula 2, G'(60°C / A) is the storage modulus at 60°C in the first region. G'(60°C / B) is the storage modulus at 60°C in the second region.

2. The adhesive film according to claim 1, wherein the first region and the second region are integrated.

3. The adhesive film according to claim 1, wherein the first region has a storage modulus of 0.01 MPa to 10 MPa at 25°C and a storage modulus of 0.005 MPa to 1 MPa at 60°C.

4. The adhesive film according to claim 1, wherein the first region has a creep of 10% or more at 60°C.

5. The adhesive film according to claim 1, wherein the second region has a storage modulus of 0.001 MPa to 1 MPa at 25°C and a storage modulus of 0.0005 MPa to 0.1 MPa at 60°C.

6. The adhesive film according to claim 1, wherein the first region comprises a photocured product of a composition for the first region comprising a monomer mixture and an initiator.

7. The adhesive film according to claim 6, wherein the monomer mixture comprises an alkyl group-containing (meth)acrylate, an alicyclic group-containing (meth)acrylate, a hydroxyl group-containing (meth)acrylate, and a heteroalicyclic group-containing vinyl monomer or (meth)acrylic monomer.

8. The adhesive film according to claim 7, wherein the monomer mixture contains 10% to 80% by weight of alkyl group-containing (meth)acrylate, 10% to 60% by weight of alicyclic group-containing (meth)acrylate, 5% to 40% by weight of hydroxyl group-containing (meth)acrylate, and 1% to 30% by weight of heteroalicyclic group-containing vinyl monomer or (meth)acrylic monomer.

9. The adhesive film according to claim 6, wherein the composition for the first region further comprises one or more crosslinking agents and silane coupling agents.

10. The adhesive film according to claim 1, wherein the second region comprises a photocured product of a composition for the second region comprising a monomer mixture and an initiator.

11. The adhesive film according to claim 10, wherein the monomer mixture comprises an alkyl group-containing (meth)acrylate, a hydroxyl group-containing (meth)acrylate, and an alkylene glycol group-containing (meth)acrylate.

12. The adhesive film according to claim 11, wherein the monomer mixture contains 10% to 80% by weight of the alkyl group-containing (meth)acrylate, 10% to 40% by weight of the hydroxyl group-containing (meth)acrylate, and 10% to 50% by weight of the alkylene glycol group-containing (meth)acrylate.

13. The adhesive film according to claim 10, wherein the composition for the second region further comprises one or more crosslinking agents and silane coupling agents.

14. The adhesive film consists of only two regions, in the order of the first region and the second region, based on the lateral direction of the outermost surface of the adhesive film. The adhesive film according to claim 1, wherein one of the outermost surfaces in the longitudinal direction of the adhesive film forms the first region, and the other of the outermost surfaces in the longitudinal direction of the adhesive film forms the second region.

15. An optical display device comprising an adhesive film according to any one of claims 1 to 14.

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